Abstract: A process for producing a transglutaminase which comprises (1) culturing a microorganism having the identifying characteristics of a microorganism selected from the group consisting of Streptomyces sp. No. 83, deposited as FERM BP-3505, Streptomyces lavendulae No. 466, deposited as FERM BP-3506, and mutants thereof, wherein the microorganism is capable of producing a transglutaminase, wherein the transglutaminase is an enzyme which catalyzes an acyl transfer reaction of a .gamma.-carboxyamide group of a glutamine residue in a peptide or protein chain in the presence or absence of Ca.sup.++ and wherein the transglutaminase has an isoelectric point of 10 or 6.8, respectively, and is inhibited by Pb ions, and (2) recovering the transglutaminase from the culture obtained is disclosed.